In order to prevent an operator from being damaged by spattering matters and various harmful rays caused by welding-arc ignition, the operator usually wears a welding helmet on his/her head before he/she carries out a welding operation.
A conventional welding helmet is usually provided with an auto-darkening filter (ADF). The auto-darkening filter generally comprises a liquid crystal panel. The liquid crystal panel is transparent in case of no welding-arc ignition. Just before the welding-arc ignition begins, the liquid crystal panel becomes opaque to protect the operator's eyes. The auto-darkening welding helmet is usually provided with a mechanically operable knob or button. Therefore, before wearing the welding helmet, the operator can set operating parameters, such as SENSITIVITY, delay time, shade, and weld mode or the like, of the auto-darkening filter by the knob or button. After the setting, the operator can wear the welding helmet on his/her head to carry out the welding operation.
This mechanically operable knob or button is generally disposed on an outer surface of a helmet housing of the welding helmet. Working environment is usually severe on welding site. When the operator wears the welding helmet to carry out the welding operation, the knob or button of the welding helmet may be most likely in contact with other workpieces or other apparatuses on site. If such contact occurs frequently, the knob or button may be damaged and thus adjustment of the auto-darkening filter will be negatively affected.
Furthermore, manipulation of the mechanically operable knob or button is relatively complex. For example, selection of a suitable operating parameter need be accomplished by first rotating and then pressing the knob or button. Such non-intuitive manipulation sometimes may increase the operator's workload.
Furthermore, if the knob or button is contacted inadvertently by the operator or the other apparatuses on site as the welding operation is being carried out, the operating parameters, which have been set beforehand, of the auto-darkening filter may be unexpectedly changed and thus the eyes of the operator may be damaged by the harmful rays.